Folding blade cylinders are employed, typically acting together with a folding jaw cylinder, for making a transverse fold in a sheet of material which is passing through a gap between the folding blade cylinder and the folding jaw cylinder. To accomplish this, at least one folding blade in the folding blade cylinder can be moved between an inactive position, in which it does not protrude outwardly past the exterior surface of the folding blade cylinder, and an active position in which the folding blade extends out past the folding blade surface. In the active position, the folding blade pushes the sheet to be folded into a gap in the oppositely located folding jaw cylinder, which gap is subsequently closed. The folding jaw cylinder then conveys the folded sheet clamped in the fold further.
In order to be able to fold sheets in various formats by the use of such a folding blade cylinder, or to form different folds, it is necessary to be able to displace the folding blade on the circumference of the folding blade cylinder between different positions. However, the exterior surface of the folding blade cylinder should be cylindrically closed to as great an extent as possible in order to assure the precise guidance of the sheets of metal.
DE 43 35 048 A1 describes a folding blade cylinder for a folding apparatus with a single gap for the folding blade. The folding blade can be displaced inside this gap in the circumferential direction of the folding blade cylinder.
DE 690 08 007 T2 shows a folding blade cylinder with a folding blade. The folding blade can be moved into a working and a rest position for different types of folds.
DE 12 22 082 A discloses a folding blade cylinder of a cylinder folding apparatus. The folding blades can be displaced, in the retracted position, in the circumferential direction in the interior of the folding blade cylinder.